Potassium (K) is a main contributor to plant growth. An abundance of potassium in the plant tissues translates to high levels in the fruit. Despite what the plant stores, when we remove the fruit from the vineyard each year, we are continually depleting the potassium. Soil composition, texture and moisture levels can also affect the availability of potassium in the soil. For these reasons, we often amend vineyard soils with potash to increase the potassium availability. Since too much potassium can lead to other deficiencies, a soil sample is needed to determine how much potassium to apply to reach the optimal level in the soil.